Typical automatic round balers, such as the models 544 and 5930 commercially available from New Holland North America, pick up crop material from a field and form it into a compacted round bale in a bale forming chamber. When the bale has been compacted to a desired density (or reached a desired size), bale density (or size) sensors send signals to a controller which in turn sends a signal to an operator's panel to signal the operator to stop forward motion of the baler so that the bale may be wrapped with netting or twine according to a program of instructions stored in a controller memory.
After a brief delay allowing time for the operator to stop forward motion of the baler, the controller initiates a wrap cycle. The mechanism for wrapping with twine includes two hollow twine tubes. Two strands of twine are fed from two twine rolls through the tubes. When a wrap cycle is initiated, the twine tubes are moved arcuately to an extended or insert position with an end of one strand dangling from the end of a respective one of the tubes. A pusher mechanism, usually referred to as a "duckbill", is actuated to move the dangling ends toward the bale so that the ends of the twine strands are adjacent the bale near its lengthwise middle. The strands are caught up in the bale which is rotating within the bale forming chamber. The bale is then wrapped in a pattern by moving the twine tubes toward a home position with programmed pauses at intervals to place circular wraps on the bale. The twine is cut after end wraps have been placed on the bale.
As the twine tubes move toward their home positions, each twine strand slides into a spring clamp and hold device so that the twine ends can not be caught up in moving machine parts after the strands are cut. Each twine is pulled out of its respective clamp and hold device at the beginning of the next wrap cycle as the twine tube arms are extended to the insert position.
It has been found that a frequent cause of failure in wrapping is due to the fact that the end of a strand does not drop quickly enough after being pulled free of its clamping device. As a result, the strand end drops onto the top of the duckbill rather than dangling in a position where it can be pushed toward the bale by the duckbill.
Hence there is a need for a system wherein the chance of failures in inserting the ends of the twine strands is considerably reduced.
The pattern in which the bale is wrapped is determined by a stored program in the controller. This program may be a factory-installed program, a "learned" program generated by manually controlling movement of the twine tubes to place the desired wrap pattern on a bale, or a factory-installed program which permits operator selection of the number of end wraps to be placed on a bale. In any event, the programs provide no easy method for restarting a twine wrap cycle to re-tie a bale in the event one or both strand ends are not caught up in the rotating bale.
Currently, the operator may wait until the selected twine pattern program completes its automatic wrap cycle and then restart the wrap cycle by actuating, for two seconds, a Wrap key on an operator's control panel. This procedure wastes a considerable amount of twine if one twine was caught up in the rotating bale. Alternatively, the operator could manually return the twine tubes to their home position by (1) actuating a Retract key on the operator's control panel to retract the twine tubes to their home position, (2) switching the controller to the net wrap mode by actuating a Net/Twine key, (3) again actuating the Retract key to return the duckbill to the home position and cut the twine, (4) actuating a Clear key to clear the error alarm and error message displayed on the operator's control panel (caused by interruption of the wrap cycle), (5) actuating the Net/Twine key to return the controller to the twine mode, and (6) initiating a new wrap cycle by actuating the Wrap key for two seconds. This complex procedure would require a very skilled and knowledgeable operator and wastes considerable time. It also wastes twine if one strand is started but, as compared to the first procedure, results in less waste.
Consequently, there is also a need for a round baler wherein the time needed to remedy failures in inserting the ends of the wrapping twine strands is considerably reduced.